Conventionally, it is known that a damping member (vibration suppression member) suppresses an undesired vibration in a piezoelectric element, in an ultrasonic transducer which transmits and receives an ultrasonic wave by using the piezoelectric element. For example, in an ultrasonic sensor 73 disclosed in Patent Literature 1, as shown in FIG. 7, an acoustic matching layer 71 is fastened to one of surfaces of a piezoelectric element 70. A tubular case 72 is fastened to the acoustic matching layer 71 so as to surround the piezoelectric element 70. An elastic resin 74 is filled in the tubular case 72 such that the piezoelectric element 70 is buried in the elastic resin 74.